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Cucumbers (Cucumis sativus) usually have female and male flowers on the same plant, meaning that they are self-pollinating and do not have to receive pollen from other plants. Cucumber pollination is complicated by hybrid cultivars with few or no male flowers, bred to increase yield, and seedless cucumbers that do not require pollination. Cucumbers can be grown in U.S. Department of Agriculture Plant Hardiness Zones 4 through 11.

Flower Description

Male and female cucumber flowers are crinkly and yellow. The male flowers grow on slender stems in clusters; each flower has three slender stamens with pollen at the end. Each female flower grows alone and has one ovary in the shape of a tiny cucumber at its base. Both male and female flowers produce nectar, but the male flowers produce more of it and theirs is sweeter. The male flowers open about 10 days before the female flowers, which outnumber the male flowers roughly 10 to 1. When cucumbers are harvested, the plant grows more flowers that yield even more cucumbers.

Monoecious Cucumbers

A standard cumber cultivar plant is monoecious, which means it contains both female and male flowers. Such cucumber plants do not need another cultivar cucumber plant for pollination. They require bees, other insects or wind, however, to spread their pollen from their male flowers to their female flowers.

Gynoecious Cucumbers

Because female flowers grow cucumbers and male flowers do not, plant breeders developed gynoecious cucumbers, which grow nearly all female flowers. These cultivars produce higher yields of cucumbers than monoecious cultivars. Some of these cultivars have a ratio of about 70 percent female flowers to 30 percent male flowers. Some other cucumber cultivars have no male flowers, and they require pollination from cultivars that produce male flowers. Packets of all-female flower cultivars often contain dyed male seeds for their simple identification, or the male seeds are in a separate packet. Commercial growers often mix gynoecious cultivars with monoecious cultivars at a ratio of about 9 to 1.

Parthenocarpic Cucumbers

Plants that produce long, seedless cucumbers originated in European greenhouses and are termed parthenocarpic, which means they yield cucumbers without pollination. These cucumber plants must be grown in greenhouses to exclude bees because pollination causes their cucumbers to become misshapen and bitter.

Cucumber Cultivar Selection

A cucumber seed packet's label states whether the package contains a variety that is monoecious, gynoecious or parthenocarpic. Unless a monoecious cultivar's cucumbers are picked when they are small, the plant will produce large cucumbers that have seeds. If you have plenty of bees in your area, then gynoecious cultivars will grow more cucumbers than monoecious cultivars. Even the skin of sweet, seedless, parthenocarpic cucumbers can be eaten, but those cultivars require a greenhouse or other enclosed location in which you can prevent bees, other pollinating insects and wind.